Error when trying to re-import a space

We're in the process of migrating a spec from one JIRA instance into another.
We have done the import once and it worked OK but now want to import again.
In order to do this we've deleted the space that was originally imported and tried to import again from the WebDav export that we've uploaded to the site.
Unfortunately when we try to import again we get the following error:

Import failed. Check your server logs for more information. com.atlassian.confluence.importexport.ImportExportException: Unable to complete import: could not insert: [bucket.user.propertyset.BucketPropertySetItem#BucketPropertySetItem[entityId=48267635,entityName=confluence_ContentEntityObject,key=confluence.inline.tasks.sequence.last,type=5,boolean=false,string=8,text=,int=0,double=0.0,long=0,date=]]

Both the source and target Confluence sites are OnDemand instances
Source: https://apigeesc.atlassian.net/wiki/display/LLBEAN
Target: https://llbean.atlassian.net

The WebDav export is still there in the Target instance if you want to try it again yourself.

Please advise how we can go ahead with doing the import again, this is blocking the migration of our customers space from our instance into theirs